Improvement in removable potances for watches



F. A. EARL. Removable Potanee for Watches.

No. 220,815. Patented Oct. 21, I879.

AZZe YZ A jnven'zar N. PETERS, PHOTO-LITHOGRAPHER, WASHINGTON. n C,

UNITED STATES PATENT OFFICE,

FRANK A. EARL, OF YPSILANTI, MIGHIGAN.

IMPROVEMENT IN REMOVABLE POTANCES FOR WATCHES.

Specification forming part of Letters Patent No. 220,815, dated October 21, 1879; application filed May 24, 187.).

To all whom it may concern:

Be it known that I, FRANK A. EARL, of Ypsilanti. in the county of Washtenaw and State of Michigan, have invented an Improvement in Removable Potances for \Vatches, of which the following is a specification.

The nature of my invention relates to certain new and useful improvements in the construction of a removable potance applicable to all watches wherein the top plate is a full plate; and the invention consists in securing the potance to a suitable plate in such manner that the potanee can be removed from the watch without the necessity of taking the watch down, all as more fully hereinafter described.

In the drawings, Figure 1 is a perspective view of the top plate of a watch with the potance and plate removed. Fig. 2 is a perspective view of the potance and its plate. Fig. 3 is a section, showing the potance secured to the plate.

In the accompanying drawings, which form part of this specification, A represents the top plate of that class of watches known as an American watch. In this plate I form the recess a and a circular aperture, 1), and in the bottom of the recess are two small apertures, c.

(l is a plate corresponding in size and shape to the recess a, and is provided upon its under face with a burr, d, corresponding in size to the aperture 0. To this burr is rigidly secured the potance D, in which is placed or secured a suitable bearing for the lower pivot of the balance-staff of a watch. 'lwo small stay-pins project from the lower face of the plate 0, which, when the latter is in place, enter the small apertures 0, the two plates 0 and A being firmly secured together by means of a proper screw, 1'.

By this construction and arrangement of parts, should a staff become broken, or the foot jewels be cracked, the repair can be easily effected by simply removing the plate and its potance, without the necessity of taking down the watch, and in this manner-a great saving of time is effected, while at the same time the danger of breaking pivots or the lever is very materially lessened over those constructions wherein the potance is rigidly secured to the top plate, or removably secured to its under face.

What I claim as my invention is-- 1. In a watch, a potance secured to the outside of the top plate, and adapted to be removed therefrom without disturbing such top plate, substantially as described.

2. In a watch, the top plate recessed on its outer face, and provided with an opening at the edge of the recess, in combination with a potance inserted through such opening from the outside, and provided with a plate secured by a screw in such recess flush with the plate, said potance being adapted for removal without disturbing the top plate, substantially as described and shown.

FRANK A. EARL.

Witnesses CHAS. R. WHITMAN, G. JosLrN. 

